Flow angle distribution
 

Hello again,

Would anyone happen to know how to produce a plot of flow angle? What I am tryuing to do is siumilar to this image I found in a research paper:

Attachment 21012

As you can see, this shows the flow angle in a constant-streamwise location.

Any ideas?

Define a variable in CFD-Post, and set it to the expression atan(Velocity U/VelocityV). Then draw this variable on a plane or whatever. You will have to change Velocity U and V to what ever direction you want to calculate the angle over.

Makes sense, thanks! I'll try that.

Is there a standard definition for the u, v and w components?

U=global X direction
V=global Y direction
W=global Z direction

So I guess VelocityU should be the tangential component and VelocityV should be the axial component to produce the angle I'm looking for. I couldn't, however, calculate the velocity components using the turbo tab (System Error: bad allocation / WARNING Action more_vars failed).

Is there some CEL command which could substitute those aforementioned components?

Also, I tried an approximation using atan(u/v) wich produced the following result:

Attachment 21013

The values are fine, but there seems to be a very small region (pointed by the red arrow) where the angle diverges significantly. Is there a way I can adjust the legend so that I get lower range and therefore a better definition?

Never mind, just changed the max and min values on the contour plot itself!

No, U and V are not defined as axial and tangential. They are defined relative to the global axis - the little XYZ gizmo in the bottom right corner of your screen. How you align this to the axial and tangential directions for your model is up to you.

Yes, I know. I did that only to arrive at an approximate angle distribution to test if the method would work fine. My question is how do I get the tangential component, given the turbo tab cannot calculate it (for some reason...)!
The axial component is global Y, so that's no brainer!

Have a look in the CFX reference manual for the available CEL variables. There are variables for rotating frames of reference and cylindrical coordinate systems.